全文获取类型
收费全文 | 38056篇 |
免费 | 1447篇 |
国内免费 | 1303篇 |
专业分类
化学 | 17430篇 |
晶体学 | 363篇 |
力学 | 1840篇 |
综合类 | 122篇 |
数学 | 10080篇 |
物理学 | 10971篇 |
出版年
2023年 | 172篇 |
2022年 | 290篇 |
2021年 | 310篇 |
2020年 | 364篇 |
2019年 | 349篇 |
2018年 | 1446篇 |
2017年 | 1713篇 |
2016年 | 1151篇 |
2015年 | 948篇 |
2014年 | 1013篇 |
2013年 | 1342篇 |
2012年 | 3938篇 |
2011年 | 3160篇 |
2010年 | 2373篇 |
2009年 | 2039篇 |
2008年 | 1180篇 |
2007年 | 1139篇 |
2006年 | 1049篇 |
2005年 | 4809篇 |
2004年 | 4258篇 |
2003年 | 2614篇 |
2002年 | 831篇 |
2001年 | 569篇 |
2000年 | 267篇 |
1999年 | 388篇 |
1998年 | 246篇 |
1997年 | 177篇 |
1996年 | 176篇 |
1995年 | 142篇 |
1994年 | 140篇 |
1993年 | 117篇 |
1992年 | 250篇 |
1991年 | 231篇 |
1990年 | 181篇 |
1989年 | 158篇 |
1988年 | 133篇 |
1987年 | 88篇 |
1986年 | 76篇 |
1985年 | 67篇 |
1984年 | 40篇 |
1979年 | 34篇 |
1976年 | 82篇 |
1975年 | 41篇 |
1974年 | 42篇 |
1973年 | 48篇 |
1972年 | 40篇 |
1970年 | 36篇 |
1969年 | 41篇 |
1968年 | 38篇 |
1966年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
S?awomir Solecki 《Topology and its Applications》2007,154(12):2462-2464
Let I0 be the σ-ideal of subsets of a Polish group generated by Borel sets which have perfectly many pairwise disjoint translates. We prove that a Fubini-type theorem holds between I0 and the σ-ideals of Haar measure zero sets and of meager sets. We use this result to give a simple proof of a generalization of a theorem of Balcerzak-Ros?anowski-Shelah stating that I0 on N2 strongly violates the countable chain condition. 相似文献
92.
93.
R. Knizikevi?ius 《Applied Surface Science》2006,253(3):1581-1583
The ion-beam-assisted etching of silicon in Cl2 environment is considered. The theoretically calculated dependences of silicon etching rate on the flux of Cl2 molecules at different ion current densities are compared with experimentally measured. The composition of the adsorbed layer is determined. It is found that SiCl2 molecules prevail in the adsorbed layer. The reciprocal of relative concentration of SiCl2 molecules in the adsorbed layer linearly depends on the ion-to-neutral flux ratio. 相似文献
94.
We consider the 3D Navier–Stokes equation with generalized impermeability boundary conditions. As auxiliary results, we prove the local in time existence of a strong solution (‘strong’ in a limited sense) and a theorem on structure. Then, taking advantage of the boundary conditions, we formulate sufficient conditions for regularity up to the boundary of a weak solution by means of requirements on one of the eigenvalues of the rate of deformation tensor. Finally, we apply these general results to the case of an axially symmetric flow with zero angular velocity. 相似文献
95.
Wei-nan E Ping-bing Ming 《应用数学学报(英文版)》2007,23(4):529-550
We study continuum and atomistic models for the elastodynamics of crystalline solids at zerotemperature.We establish sharp criterion for the regime of validity of the nonlinear elastic wave equationsderived from the well-known Cauchy-Born rule. 相似文献
96.
Nikolaií N. Nekhoroshev Dmitrií A. Sadovskií Boris I. Zhilinskií 《Annales Henri Poincare》2006,7(6):1099-1211
We introduce fractional monodromy in order to characterize certain non-isolated critical values of the energy–momentum map
of integrable Hamiltonian dynamical systems represented by nonlinear resonant two-dimensional oscillators. We give the formal
mathematical definition of fractional monodromy, which is a generalization of the definition of monodromy used by other authors
before. We prove that the 1:( − 2) resonant oscillator system has monodromy matrix with half-integer coefficients and discuss
manifestations of this monodromy in quantum systems.
Communicated by Eduard Zehnder
Submitted: February 25, 2005; Accepted: November 17, 2005 相似文献
97.
Hong Ming ZHANG Xian Hong WANG Xiao Jiang ZHAO Ji LI Fo Song WANG 《中国化学快报》2006,17(4):437-440
A novel method for the preparation of oligothiophene molecular wires is described via a bi-directional solid-phase synthesis. Using an alternating sequence of bromination and Stille coupling reactions, oligomers were obtained up to the heptamer in excellent yield and purity. 相似文献
98.
99.
M. A. Rizzutto N. Added M. H. Tabacniks F. R. Espinoza-Qui?ones S. M. Palacio R. M. Galante R. M. Galante N. Rossi R. A. Welter A. N. Módenes 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(3):727-731
Summary Kulcsszavak (angolul, ha nem azonos az elozovel) 相似文献
100.